Fertilisation and environmental factors affect the yield and quality of alfalfa in China

Alfalfa (Medicago sativa L.) is a superior-quality perennial legume forage crop cultivated in China. However, fertiliser applications and the environmental factors affecting alfalfa yield and quality have not been well documented. In this study, we conducted a meta-analysis using a dataset from 105 studies published between 2003 and 2023 to explore the effects of fertiliser application and environmental factors on the yield and quality of alfalfa. The results showed that compared to the non-fertiliser control levels, fertiliser application increased alfalfa yield by 24.61% and improved the quality of alfalfa by increasing crude protein by 11.63% and decreasing acid detergent fibre by 7.69% and neutral detergent fibre by 6.76%. Alfalfa yield and the crude protein effect size increased with increasing altitude but decreased with increasing latitude based on fertiliser application. The acid detergent fibre and neutral detergent fibre effect size were positively correlated with mean annual temperature and mean annual precipitation. In conclusion, applying fertiliser is a productive approach to enhance the yield and grade of alfalfa, but environmental factors have an effect. This study provides comprehensive information on fertiliser applications and environmental factors that affect alfalfa yield and quality. These results provide insight into further improving alfalfa yield and quality and contribute to the development of alfalfa.